JP2009234026A - Electrostatic suction type ink jet head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrostatic suction type ink jet head, supplying ink to the tip of a nozzle at a low voltage and performing record printing with required printing quality. <P>SOLUTION: The surface tension of ink liquid is controlled utilizing an electrowetting effect, whereby ink in a nozzle 10 is discharged and ink is selectively supplied to the inside of the nozzle, and the ink supplied to the tip of the nozzle is electrostatically sucked and flied to perform record printing. Further, the inside shape of the nozzle is made tapered as it goes forward, whereby capillary force is inclined. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electrostatic suction type ink jet head that performs electrostatic printing by charging ink and electrostatically sucking the ink and performing recording printing on printing paper.

  Various types of electrostatic suction ink jet heads of this type have been known. For example, an electrode is provided on the side surface of the nozzle, and a controlled voltage is applied between the nozzle and the solution in the nozzle, so that the solution is supplied to the tip of the nozzle by the electrowetting effect. In addition, there is known a technique in which an electric field is concentrated by reducing the discharge diameter of the charged solution supplied to the nozzle tip, and the image is printed on printing paper by causing it to fly as an ink drop by mirror image force. (For example, refer to Patent Document 1).

Japanese Patent Laid-Open No. 2004-165588

  However, in the conventional structure described above, since the electrowetting effect is obtained using the nozzle wall that is an insulator, the wall thickness and the material are limited, and the applied voltage is increased in order to obtain a sufficient effect. There is a need. This is because the electrowetting (EWOD: Electro Wetting On Dielectrics) effect becomes more prominent as the insulator is thinner and the dielectric constant is higher.

Further, in order to cause ink droplets to fly using mirror image force, it is necessary to make the distance between the nozzle tip and the printing paper very small.
Further, since the ink discharge port is a nozzle, there is a problem that clogging is likely to occur.

  The present invention has been made in view of such circumstances, and in an electrostatic suction type inkjet head, ink is selectively supplied to the tip of a nozzle at a low voltage, and the required print quality is obtained by electrostatic discharge. It is an object of the present invention to obtain an electrostatic suction type ink-jet head that performs recording printing having the above.

  In order to meet such an object, the electrostatic attraction type inkjet head according to the present invention (the invention according to claim 1) controls the surface tension of the ink liquid, thereby discharging the ink in the nozzle and discharging it into the nozzle. The ink is selectively supplied and recording is performed by electrostatically sucking the ink supplied to the nozzle tip.

  The electrostatic attraction type inkjet head according to the present invention (the invention according to claim 2) controls the surface tension of the ink liquid, thereby discharging the ink in the slit and selectively supplying the ink into the slit. Recording is performed by electrostatically attracting ink supplied to the tip of the slit.

  The electrostatic attraction type ink jet head according to the present invention (invention of claim 3) is characterized in that in claim 1 or claim 2, the surface tension of the ink liquid is controlled by utilizing an electrowetting effect. Be

  An electrostatic attraction type ink jet head according to the present invention (invention according to claim 4) is the capillary suction force according to any one of claims 1 to 3, wherein the nozzle inner shape becomes narrower toward the tip. It is characterized by having an inclination.

  An electrostatic attraction type ink jet head according to the present invention (invention according to claim 5) is a parallel plate-shaped ink jet head according to any one of claims 1 to 3, wherein the slit interval becomes narrower toward the tip. It is characterized in that the capillary force is inclined.

  The electrostatic attraction type ink jet head according to the present invention (the invention according to claim 6) selectively causes a minute wave on the liquid surface of the conductive ink, and applies a uniform electric field thereto to cause an edge effect. Concentrating the electric field on the convex part of the wave on the liquid level, increasing the electrostatic force and further growing the convex part, forming a tailor cone and recording with ink droplets flying from its tip Features.

  An electrostatic attraction type ink jet head according to the present invention (invention of claim 7) is characterized in that, in claim 6, the surface property of water repellency and hydrophilicity is controlled at low voltage by utilizing the electrowetting effect, It is characterized by causing a change in the meniscus, causing a minute wave on the ink surface, and using this as a trigger for ink flight.

  An electrostatic attraction type inkjet head according to the present invention (invention according to claim 8) has the pixel electrodes insulated by dielectric layers above and below the slit-like ink discharge port in claim 6 or claim 7, It is characterized by a line type slit head configuration in which the slit tip is water-repellent coated.

  As described above, according to the electrostatic attraction type inkjet head according to the present invention, by using the electrowetting effect, ink is selectively supplied to the nozzle tip at a low voltage, and this is electrostatically ejected for recording. Therefore, there are various excellent effects as follows.

  That is, according to the present invention, by controlling the surface tension of the ink liquid, the ink in the nozzle is discharged and the ink is selectively supplied to the nozzle, and the ink supplied to the nozzle tip is electrostatically attracted. Therefore, if the contact angle between the inner wall of the capillary and the ink liquid is larger than 90 °, the ink liquid does not penetrate into the capillary tube, and the surface tension of the ink liquid is lowered and the contact angle is made smaller than 90 °. The ink can be selectively supplied by utilizing the phenomenon of penetration into the capillary tube.

  In particular, since an electrode for electrowetting effect and a thin film of high dielectric constant dielectric are formed on the inner wall of the nozzle, the electrowetting effect can be exhibited at a low voltage.

  In addition, according to the present invention, the surface of the high dielectric constant thin dielectric layer is provided with a water repellent coating (no coating is required when the dielectric is water repellent), and when the voltage is off, the ink is transferred from the nozzle to the ink chamber. By discharging and applying a voltage, the ink can be supplied to the nozzle tip in a desired state.

  In addition, according to the present invention, the capillary inner force is inclined by making the inner shape of the nozzle thinner toward the tip, so that when the voltage is off, the nozzle surface tension and water-repellent surface The ink inside is urged to be discharged into the ink chamber, and when the voltage is on, the ink supply to the nozzle tip is assisted.

  Furthermore, according to the present invention, the surface tension of the ink liquid is controlled using the electrowetting effect, that is, the electrode inner wall and the dielectric thin layer are formed on the inner wall of the nozzle, and the surface The coating is made with a water-repellent coating (if the dielectric is water-repellent, the coating is not necessary). The thinner the dielectric, the larger the dielectric constant, the greater the electrowetting effect, and the lower the voltage. Become possible

  According to another aspect of the present invention, recording is performed by selectively supplying ink to the tip of the slit along the fine electrodes arranged above and below the slit using the electrowetting effect and electrostatically ejecting the ink. Therefore, by controlling the surface tension of the ink liquid, it is possible to discharge the ink in the slit and selectively supply the ink into the slit, and perform recording by electrostatically sucking the ink supplied to the slit tip. it can.

  In particular, according to the present invention, the ink flow paths are all between the slits, and there is an advantage that the occurrence of clogging is very small compared to the nozzle method.

  That is, according to the present invention, when the contact angle between the inner wall of the capillary and the ink liquid is larger than 90 °, the ink liquid does not penetrate into the capillary tube, the surface tension of the ink liquid is lowered, and the contact angle is increased from 90 °. The ink can be selectively supplied by utilizing the phenomenon that the penetration into the capillary tube is reduced.

  In addition, according to the present invention, since the surface tension of the ink liquid is controlled using the electrowetting effect, an electrode for electrowetting and a thin layer of dielectric are formed on the inner wall of the slit. Water repellent coating is applied to the surface (coating is not required if the dielectric is water repellent). At this time, the thinner the dielectric film, the greater the dielectric constant, the greater the electrowetting effect and the lower the voltage Becomes possible

  Further, according to the present invention, the slit interval is made narrower toward the tip, and the parallel plate-like capillary force is inclined, so that when the voltage is off, the slits are caused by the surface tension of the ink and the water repellent surface. The ink inside can be urged to be discharged into the ink chamber, and the supply of ink to the slit tip can be assisted when the voltage is on.

  Furthermore, according to another aspect of the present invention, since the meniscus of the liquid surface is changed by the electrowetting effect and is used as a trigger for the ink droplet flight, a minute wave is selectively generated on the liquid surface of the conductive ink, When a uniform electric field is applied, the electric field concentrates on the convex part of the wave on the liquid surface due to the edge effect, the electrostatic force increases, the convex part grows further, and finally a tailor cone is formed, flying from its tip The required recording can be performed by the ink droplets.

  Furthermore, according to the present invention, the surface property (water repellency / hydrophilicity) is controlled at a low voltage by utilizing the electrowetting effect, causing a change in the meniscus of the liquid surface, and generating a minute wave on the ink liquid surface. Since this is used as a trigger for ink flight, all the ink flow paths are between the slits, and clogging is very small compared to the nozzle method.

  In addition, according to the present invention, the structure is very simple because it has a pixel electrode insulated by a dielectric layer above and below the slit-like ink discharge port and has a water-repellent coating on the slit tip. It is simple, and a high-resolution head can be easily realized by photolithography.

  1A and 1B show an embodiment of an electrostatic suction ink jet head according to the present invention.

In these drawings, reference numeral 10 denotes one nozzle constituting a multi-nozzle head, and a nozzle electrode 11, a dielectric layer 12, and a water repellent (ink) layer 13 are formed on the inner surface of a base material constituting the nozzle 10. Is formed.
Here, one nozzle 10 and one nozzle electrode 11 are provided for each pixel, and one Sw1 element and Sw2 element are provided for each pixel, or one pixel is provided for a plurality of pixels by a time division control method. May be.

Reference numeral 15 denotes an ink chamber, and a common drive electrode 16 and a common control electrode 17 are provided on the back side thereof. Further, 18 is a printing paper, and 19 is a counter electrode.
Note that a control power supply Vc, a common drive power supply Vk, a bias power supply Vb, and the like are appropriately connected to the electrodes described above. Furthermore, the Sw3 element has one common to all pixels in the entire head 1.

  FIG. 2 illustrates the movement of the ink jet head described above. Here, the ink chamber 15 is filled with ink from an ink tank (not shown) by capillary force or a pump (not shown).

  In such a configuration, in the state A shown in FIG. 5A, the Sw1 element is switched to the A side, the Sw3 element is switched to the F side, and the Sw2 element is switched to the D side, and the charge in the ink is discharged. As a result, the ink liquid is in a standard surface tension state by discharging, and cannot enter the nozzle 10 on the surface of the water repellent (ink) layer, but waits at the inlet of the nozzle 10.

In the state B shown in FIG. 5B, the Sw2 element corresponding to the pixel to be recorded is switched to the E side. A voltage is applied between the ink liquid and the nozzle electrode 11 to develop an electrowetting effect, the surface tension of the ink is lowered, the ink penetrates into the nozzle 10 and is supplied to the tip portion.
When no control voltage is applied, the ink remains in state A.

  The above-described decrease in surface tension is expressed by the following equation (Equation 1) in terms of the contact angle.

  For example, a head is constructed using a high dielectric constant insulating sheet (relative dielectric constant = 45, film thickness = 10 μm) in which a high dielectric constant filler (such as barium titanate) is highly filled in epoxy resin, and the surface tension of ink is standard. Table 1 below shows changes in the contact angle with a small value of 20 mN / m and a contact angle of 90 ° when the voltage is off.

  That is, transition from a water-repellent (ink) property with a contact angle of 90 ° to a hydrophilic (ink) property by application of a low voltage.

  The penetration phenomenon into the nozzle is expressed by the following Lucas-Washburn equation (Equation 2).

From this, the penetration distance and penetration time of the ink into the nozzle 10 when the contact angle is changed to 77.0 ° with an applied voltage of 15 V in the example of Table 1 are as shown in Table 2.
Here, the nozzle was regarded as a capillary having a diameter of 100 μm.

In such a state, if A4 paper, lateral feed, 600 dpi, and 30 ppm are used, it is necessary to print one dot line within a processing time of 325 μs.
Further, since it is necessary to consider the penetration and discharge of ink, it is necessary to finish each within about 150 μs. At this time, from Table 2, the penetration distance can be about 900 μm in this time (150 μs). Therefore, under these conditions, 900 μm can be secured by the difference in the position of the liquid surface tip in the nozzle between the printed dot and the non-printed dot, and the nozzle length is set to 900 μm.

  Next, in the state C shown in FIG. 5C, the Sw1 element is switched to the B side and the Sw2 element is switched to the C side. Thereafter, the Sw3 element is switched to the G side, and the common drive power is applied to the common drive electrode, whereby only the ink that has moved to the tip of the nozzle in state B is electrostatically ejected.

Next, the Sw1 element is switched to the A side, the Sw2 element is switched to the D side, and the Sw3 element is switched to the F side to return to the state A and wait for the next printing.
At this time, by discharging the charge in the ink, the surface tension of the ink returns to the standard value. Due to the water repellency (ink) property of the inner wall of the nozzle 10 and the inclination of the inner diameter of the nozzle 10, the ink in the nozzle 10 becomes the ink. It is discharged into the chamber 15.

  Next, as described above, printing is performed by repeating the states A to C corresponding to the image data.

  The distance between the tip of the nozzle 10 and the recording medium is the same as that of the conventional electrostatic attraction type ink jet method using the electrohydrodynamic instability of the liquid surface at the tip of the nozzle 10 and can be about 0.2 mm to 2 mm. .

According to the above configuration, the print pixel dot can be selected with a low voltage of about 10 to 20V.
In particular, the voltage is very low compared to the conventional electrostatic attraction method, and the switching element can be configured at low cost.
Further, the distance between the nozzle tip and the recording medium can be up to about 2 mm, which improves the designability and manufacturability.

FIG. 3 shows a modification of the nozzle part configuration of the multi-nozzle head.
That is, the upper and lower wall surfaces of the nozzle 10 are parallel, and the electrowetting electrode 11 and the dielectric layer 12 are formed on the bottom surface of the upper substrate and the bottom surface of the groove of the lower substrate. Further, the gap between the left and right side surfaces of the nozzle 10 is narrowed toward the tip, and the capillary force is inclined. Further, a water repellent (ink) coating is applied to the inner wall of the nozzle 10.
And an upper base material and a lower base material are processed separately, and are finally joined and completed.
By adopting such a configuration, it becomes easy to manufacture a multi-head nozzle.

4 to 6 show another embodiment of the electrostatic suction type ink jet head according to the present invention. In this embodiment, the head is the slit head 20 and the ink discharge port is the above-described embodiment. This is the case where the slit-like ink discharge port 21 is used instead of the nozzle.
However, since the other configuration is substantially the same as the nozzle 10 in the above-described embodiment, the same or corresponding parts are denoted by the same reference numerals and detailed description thereof is omitted.

  Here, the pixel electrodes 22 and 23 have one pair for each pixel, and one Sw1 element and Sw2 element are provided for each pixel, or one pixel is provided for each pixel by a time division control method. May be. Further, the control power source Vc, the common drive power source Vk, the bias power source Vb, the common drive electrode 16, the common control electrode 17, the counter electrode 19, the ink chamber 15, and the Sw3 element are provided in common for all the pixels in the entire head 20.

  In the configuration described above, the operation is as shown in FIG. Here, the operation of the slit head 20 is substantially the same as that of the nozzle 10 in the above-described embodiment, and detailed description thereof is omitted.

Here, in this embodiment, since the ink permeates between the slits along the pixel electrodes 22 and 23, it is not strictly a capillary permeation phenomenon. However, since the slit interval is narrow (about 100 μm), it is described above. It can be approximated as a phenomenon substantially equivalent to the embodiment.
Further, 900 μm can be secured by the difference in position of the liquid surface tip in the slit in this embodiment, and the length of the slit-like ink discharge portion 21 is set to 900 μm.

Furthermore, in this embodiment, by discharging the charge in the ink, the surface tension of the ink returns to the standard value. Due to the water repellency (ink) property of the inner wall of the slit and the inclination of the slit interval, the ink in the slit becomes the ink chamber. 15 is discharged.
Then, printing is performed by repeating the states A to C corresponding to the image data.
The distance between the slit tip and the recording medium is the same as that of the conventional electrostatic attraction type ink jet method utilizing the electrohydrodynamic instability of the liquid level at the nozzle tip, and can be about 0.2 mm to 2 mm.

Even with such a configuration, there are substantially the same effects as the above-described embodiment.
In this embodiment, the distance between the slit tip and the recording medium can be up to about 2 mm, which improves designability and manufacturability.
Further, in this embodiment, all the ink flow paths are between the slits, and there is an advantage that the occurrence of clogging is very small as compared with the nozzle method.

FIG. 7 shows still another embodiment of the present invention, and this embodiment is also a case of a slit head 20 called a line type head.
Here, the pixel electrodes 22 and 23 have a pair of upper and lower for each pixel, and are insulated from the conductive ink by the dielectric layer 12.

Further, a water repellent coating 13 is applied to the tip of the slit as shown in the figure.
One Sw1 element may be provided for each pixel or may be provided at a ratio of one for a plurality of pixels by a time division control method.

Further, the head 20 as a whole has one control power source Vk, bias power source Vb, control electrode 25, counter electrode 19, ink chamber 15, Sw2 element, and Sw3 element.
In addition, a recording paper 18 is disposed between the slit head 20 and the counter electrode 19, and recording is performed thereon by ink droplets flying toward the counter electrode 19.

  The operation of the slit head 20 in such an embodiment is as shown in FIGS.

That is, the ink chamber 15 is filled with ink from an ink tank (not shown) by a pump or the like (not shown).
Here, due to the positive pressure applied to the ink chamber 15 and the water-repellent coating 13 at the slit tip, the liquid surface shape at the tip of the slit becomes convex as shown in the figure. In this state, the control power is turned on (Sw2 on the D side). ) These power supply values are adjusted so that the ink does not fly toward the counter electrode even when the bias power supply is turned on (Sw3 is short-circuited).

In the “standby state” shown in FIGS. 8A and 9A, the following is performed.
That is, the Sw1 element is switched to the A side and the Sw2 element is switched to the E side, and the charge injected into the ink during the previous dot printing operation is discharged. By discharging the ink, the electrowetting effect is lost, and the liquid level at the slit tip becomes convex. Further, the Sw3 element is switched to open to prepare for the next printing operation.

  Next, the Sw1 element corresponding to the print pixel corresponds to the A side and the non-print pixel as shown in “print / non-print pixel selection” shown in FIGS. 8B-1 and 9B. At the same time as switching the Sw1 element to the C side, the Sw2 element is switched to the D side. Then, charges are injected from the control electrode 25, the Sw1 element is switched to the A side, the charges are concentrated on the print pixels connected to the GND, an electrowetting effect is exhibited, and the wettability of the portion is inclined to be hydrophilic, The shape of the liquid level at the slit tip becomes concave.

  Here, as shown in FIG. 8 (b-1), the non-printing pixel electrode portion having the same potential as that of the control electrode 25 has no concentration of electric charge, no change in wettability, and water repellency, and the slit tip. The liquid level of the liquid has a convex surface.

  Next, as shown in “Ink Drop Flying” shown in FIGS. 8 (c-1, c-2), 9 (c), (d), and (e), the Sw1 element of the print pixel is placed on the B side. By switching and making the electrode floating, the electrowetting effect is lowered, and the liquid surface tends to return from the concave surface to the original convex surface. At this time, as shown in FIG.

  At this time, by short-circuiting the Sw3 element and turning on the bias power supply Vb, the electric field is concentrated on the minute convex portion of the surface wave due to the edge effect, the electrostatic force is increased, and the convex portion is further elongated. As shown in (d), the stringing phenomenon begins.

  When the stringing phenomenon starts, a tailor cone is finally formed, and as shown in FIG. 9 (e), droplets start to fly from the tip toward the counter electrode, and are printed on the recording paper in between.

  On the other hand, even if the non-printing pixel in which the electrowetting effect does not appear, even if the Sw1 element is switched to the B side, the surface of the liquid surface does not wave, the curvature of the convex portion of the liquid surface is large, the edge effect does not work, Ink droplets do not fly because they do not grow into a whispering phenomenon.

As described above, printing is performed by repeating the above state corresponding to the image data.
This change in wettability is expressed by the following equation (Equation 1) when expressed in relation to the contact angle.
(For example, see JournalofAppliedPhysics.Vol.92, No.7,2002pp.4080-4087)

  For example, a head is constructed using a high dielectric constant insulating sheet (relative dielectric constant = 45, film thickness = 10 μm) in which a high dielectric constant filler (such as barium titanate) is highly filled in epoxy resin, and the surface tension of ink is standard. Table 3 below shows changes in the contact angle with a small value of 20 mN / m and a contact angle of 110 ° when the voltage is off.

That is, it is possible to shift from a water-repellent (ink) property with a contact angle of 110 ° to a hydrophilic (ink) property by applying a low voltage.
Therefore, in this method, the voltage of the control power supply can be realized at about 30 V, and pixel printing / non-printing can be selected at a very low voltage compared with other electrostatic ink jet methods.

  Considering the distance to the counter electrode and the applied voltage as shown in FIG. 10, the slit interval: d is expressed by the following equation (Equation 4). (For example, see Journal of the Institute of Image Electronics Engineers of Japan, Vol. 17, No. 4, 1988, pp. 185-193)

When the distance h from the counter electrode is 0.5 [mm], the surface tension γ is 20 [mN / m], and the applied voltage Vb is 3 [kV],
d> 197 μm
Therefore, the slit interval is 200 μm or more.

  In this embodiment, the slit type head 20 is assumed, but the nozzle type can be operated without any problem even if the pixel electrodes are separated by partition walls.

  According to such an embodiment, a print pixel dot can be selected with a low voltage of about 30V. In particular, the voltage is very low compared to the conventional electrostatic attraction method, and the switching element can be configured at low cost.

In addition, the ink flow paths are all between the slits, and clogging is very small compared to the nozzle method.
Furthermore, the structure is very simple, and a high-resolution head can be easily realized by photolithography.

FIG. 11 illustrates a modification of the above-described embodiment.
In other words, the pixel electrodes above and below the slit are usually arranged to face each other as shown in FIG. 11A, but instead of the pixel electrodes arranged to face each other as shown in FIG. You may arrange in.
In this way, since each corresponds to one pixel, the drive voltage value needs to be somewhat increased, but the required number of Sw1 elements is halved.

  Note that the present invention is not limited to the structure described in the above-described embodiment, and it goes without saying that the shape and structure of each part constituting the electrostatic suction ink jet head can be appropriately modified and changed.

1 shows an embodiment of an electrostatic attraction type ink jet head according to the present invention, wherein (a) and (b) are a schematic cross-sectional view showing one nozzle when a multi-nozzle head is configured and an enlarged view of a main part thereof. (A), (b), (c) is explanatory drawing explaining the motion of the multi-nozzle head of FIG. 1A and 1B show a modification of the nozzle part of the multi-nozzle head of FIG. 1, wherein FIG. 1A is a front view, a top view, a rear view, and two side views, and FIG. 1B is a top view showing a nozzle configuration, AA ′, B It is -B 'sectional drawing. 2 shows another embodiment of the electrostatic suction type ink jet head according to the present invention, wherein (a) and (b) are a detailed view of one slit-like ink discharge port and a partially enlarged view thereof. FIG. 5 is a schematic perspective view of the electrostatic suction type inkjet head of FIG. 4. (A), (b), (c) is explanatory drawing explaining the motion of the multi-nozzle head of FIG. FIG. 4 shows still another embodiment of the present invention, in which (a) is a cross-sectional view of the main part showing one slit-like ink discharge port in the line type head, and (b) is an enlarged view showing the slit head part. It is a figure for demonstrating the operation | movement with the slit head of FIG. It is explanatory drawing which shows the behavior of the meniscus of a slit front-end | tip. It is explanatory drawing explaining the slit space | interval d. It is a front view of the slit front-end | tip.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Multi-nozzle head (nozzle), 11 ... Nozzle electrode, 12 ... Dielectric layer, 13 ... Water-repellent (ink) layer, 15 ... Ink chamber, 16 ... Common drive electrode, 17 ... Common control electrode, 18 ... Printing paper , 19 ... Counter electrode, 20 ... Slit head, 21 ... Slit ink discharge port, 22, 23 ... Pixel electrode, 25 ... Control electrode.

Claims (8)

By controlling the surface tension of the ink liquid, the ink in the nozzle is discharged and the ink is selectively supplied into the nozzle.
An electrostatic suction type ink jet head that performs recording by electrostatically sucking ink supplied to a nozzle tip. By controlling the surface tension of the ink liquid, the ink in the slit is discharged and the ink is selectively supplied into the slit.
An electrostatic attraction type ink jet head for performing recording by electrostatic attraction of ink supplied to a slit tip. In the electrostatic attraction type inkjet head according to claim 1 or 2,
An electrostatic suction type inkjet head characterized in that the surface tension of an ink liquid is controlled using an electrowetting effect. The electrostatic attraction type inkjet head according to any one of claims 1 to 3,
An electrostatic suction type inkjet head characterized in that the capillary inner force is inclined so that the inner shape of the nozzle becomes thinner toward the tip. The electrostatic attraction type inkjet head according to any one of claims 1 to 3,
An electrostatic attraction type ink jet head characterized in that the slit spacing becomes narrower toward the tip, and the parallel plate capillary force is inclined. A minute wave is selectively generated on the liquid surface of the conductive ink,
Applying a uniform electric field there, the electric field is concentrated on the convex part of the wave on the liquid surface by the edge effect,
As the electrostatic force increases and the protrusions grow further, a tailor cone is formed,
An electrostatic attraction type ink-jet head configured to perform recording with ink droplets flying from the tip thereof. In the electrostatic attraction type inkjet head according to claim 6,
Control the water repellent and hydrophilic surface properties at low voltage using the electrowetting effect,
Change the meniscus of the liquid level,
An electrostatic attraction type ink jet head characterized in that a minute wave is generated on an ink surface and used as a trigger for ink flight. In the electrostatic attraction type inkjet head according to claim 6 or 7,
Has pixel electrodes insulated by dielectric layers above and below the slit-like ink discharge port,
An electrostatic suction type ink jet head characterized in that it has a line type slit head configuration in which the slit tip is water-repellent coated.

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